Field of the Invention
The present invention relates to pneumatic tires, and in particular, relates to a pneumatic tire having a tread main groove that may prevent stone-biting.
Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2010-18125 discloses a pneumatic tire which includes a tread portion provided with a circumferentially and continuously extending main groove. In order to avoid stone-biting into the main groove, the main groove includes a pair of groove walls each of which includes a radially inner steep sloped wall and a radially outer gentle sloped wall, wherein the radial height of the gentle sloped wall is periodically varying in a longitudinal direction of the main groove.
Unfortunately, the groove wall configuration described above is not sufficient to prevent the stone-biting for pneumatic tires for use on gravel and the like.